On the S W foothills of Mt. Menikion and the NE part of Serres basin, four zones of composite alluvial fans have been formed. The upper zone of thick hard fanglomerates lies at altitudes of 280 to 600 m on Mt. Menikion schists and marbles. The high zone of loose fanglomerates, with red-brown sand matrix, lies at altitudes of 200 to 350 m on the neogene deposits. The intermediate zone of mixed coarse and fine elastics lies at altitudes of 80 to 140 m on neogene deposits. The lower zone of gravel, sand and silt deposits lies at altitudes of 10 to 60 m on quaternary terrace deposits. Each zone is approximately 13 - 17 km long and 1-2 km wide, with E/SE - W/NW trend, almost parallel to the main fault lines of the area. The fan zones were deposited along the slopes of Mt. Menikion and Serres basin, owing to the fault tectonics of the area. Several E/SE - W/NW trending parallel to each other listric faults, were formed on the basement on Mt. Menikion and the neogene deposits of Serres basin. Their blocks slided and turned downstream along the faults, so that their surface inclined backwards. Close to the faults, parallel valleys were formed. They filled up with quaternary deposits, brought down by activated torrents. The torrents flowed transversely to the fault blocks. At the inner parts of the blocks they deposited clastic material in the form of alluvial fans. In the outer – higher part of the blocks they were incised in the rocks or the neogene sediments, to form narrow valleys, with terraces along their walls. The staircase development of the relief finally resulted in a staircase development of the fan zones. The two zones, upper and high, seem to be Pleistocene in age and the torrents have already incised in the fan material. The two zones, intermediate and lower, seem to be Holocene in age and are still active. Tectonic activity seems to have been the main cause of sediment entrapment in the Serres basin and the low sediment delivery rate of the river Strymon during the Quaternary.

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Mesologi lagoon is a large and shallow environment with intense fish farming applications and the consequent enclosing of very large areas with fish fences and nets, which make field mapping almost impossible. Anthropogenic influence is eminent and a recent and updated morphological map was necessary. A mapping technique is presented based on the use of astronaut photography that is distributed freely by the Internet site of NASA. The digital photograph was geometrically corrected, visually, as semi transparent layer over a scanned map image by the use of PHOTOSHOP software. The areas of known depth were used to classify the depths of the lagoon with the PHOTOSHOP tool "replace color". An image therefore was produce with the depths classified as solid colors. This image was used as base map in MAPINFO, to produce a digital map in GIS environment, where all anthropogenic influence and depths (as depth ranges) are exist as separate layers and reveal the morphological background of the lagoon. The GIS map was used to calculate the water volume of the lagoon and the changes of the volume, as the sea level fluctuates with the tide. The depth-volume diagram was created and shows that during low water (-30cm) the volume is reduced by 43%, in contrast an increase of only 12% when sea level become 30cm higher. This is the result of the construction of peripheral embankments that restricts extension of the lagoon in high water. The implication of this situation is that the water renewal is restricted when sea level is kept high by a barometric low or an onshore wind, in contrast to very good renewal time when sea level is kept low by a barometric high.

The reservoir of Platanovrysi in the Nestos valley has a long and narrow shape, limited in area and volume, deep close to the dam wall (90 m) and very shallow at its uphill end (5m). It receives considerable volume of water from the upper large reservoir of Thesaurus all through the year, as well as limited volumes of water in seasonal flows from its drainage basin. Platanovrysi reservoir has distinct morphological and operational characteristics that make it different from natural lakes regarding temperature and dissolved oxygen distribution in the water column. The epilimnion is limited at the area of the deeper part of the lake only. It forms an entrapped warm wedge, with the maximum depth close to the dam and a horizontal extension up to the beginning of the shallow part of the lake. This is due to both the inflows of large volumes of cold water from Thesaurus as well as the lack of a surface outflow from the dam of Platanovrysi. The water temperatures of the surface water of the upper part of the lake as well as the temperatures of the hypolimnion are similar. The temperature is very low during the spring and the summer (6-7°C), becomes higher during autumn (14-15°C) and drops again during winter (9-10°C). This shifting of seasonal temperatures is purely due to the inflows of cold water from the hypolimnion of the reservoir of Thesaurus in spring and summer periods and from the base of epilimnion during autumn. The water is rich in oxygen during the spring and the summer while it becomes poor in oxygen during the autumn and the beginning of winter. The operation of Platanovrysi Power Station allows the cold water from the hypolimnion of the lake to flow into the river Nestos channel and brings cold water during the warm period of the year downstream. This type of change of the water temperature may affect the natural processes of the river fauna and flora as well as the human processes in the plains of Nestos (irrigation). It is therefore necessary to construct and operate the last (lower) reservoir of Temenos in Nestos, to regulate the flow and warm the water of the river Nestos channel.

The hazard of erosion in the Xeropotamos river drainage basin on the eastern side of Kastoria lake is examined in this paper, through G.I.S. techniques (methodology).Eight levels of information were taken into account: The channel network, the Digital Elevation Model (DEM through TIN), the surface slope degree and orientation, the lithology, the vegetational cover, the rainfall distribution and the wind blown factors.The combination of the above levels of information allowed the production of two alternative erosional hazard assessment maps. One counts for equal and another counts for not equal influence of all the above factors in the model. The erosional capacity of Xeropotamos is reflected on the flatlands of the eastern side of Kastoria lake,where the river deposits heavy sediment loads, thus forming a deltaic lobe into the lake. It threatens to split the lake, unless antierosional measures on the drainage basin reduces its capacity.